Various styles of shipping containers are known in the prior art, including the so-called Bliss-style container in which a wrapper is folded around and stapled or glued to a pair of end pieces to form an enclosed container. The end pieces normally comprise flat panels that form the end walls in the container, and the wrapper forms the bottom wall, sidewalls and top wall. Flanges on opposite edges of the wrapper are folded and glued or otherwise fastened to the end wall panels to secure the wrapper and end pieces together. The flanges fastened against the end wall panels in the corners of the container serve to strengthen the container in comparison to a typical box that is folded from a single blank and has single panel thickness in the end walls and sidewalls. Compression or stacking strength of the container normally is enhanced by orienting the corrugations of the wrapper so that they extend vertically, but this sometimes results in an inefficient utilization of corrugator width during manufacture of the container.
Another common style of shipping container is the so-called Defor™ container made by International Paper Company. The Defor™ container typically is formed from a single blank that is folded to form double thickness end walls and/or sidewalls and therefore normally has greater strength than a Bliss-style container, although it requires more material in its manufacture. Stacking tabs normally project from the upper edges of the end walls or sidewalls and notches in the lower edges receive the stacking tabs when two or more containers are stacked on top of one another. One of the panels forming a part of the end walls or sidewalls can be folded to form a diagonal panel in each corner to lend greater stacking strength to the container. Other examples of prior art are disclosed in Assignee's prior patents U.S. Pat. Nos. 6,598,785; 5,752,648; 4,417,686.
Some Bliss-style containers have modified corners wherein a diagonal corner panel extends across each corner to increase the stacking strength, but in these conventional modified corner Bliss-style containers there is nothing behind the angled panel except the edge of the wrapper and the wrapper flange that is secured to the end panel. Moreover, these modified corner design of the flanges on the wrapper must be relatively wide to reach past where the diagonal corner panel joins the end panel. This results in weak areas in the bottom of the container at each corner.
Accordingly, there is need to for a container that has superior stacking strength and resistance to distortion when transverse forces are applied to the ends or sides of the container.